- All tumors should be removed by either a mastectomy or local excision plus an acceptable axillary procedure (i.e., sentinel lymph node biopsy, axillary dissection, or both); there must be adequate (at least 1 mm if margin width specified) tumor-free margins of resection (for invasive and ductal carcinoma in-situ) in order for the patients to be eligible; patients with lobular carcinoma in-situ involving the resection margins are eligible